[porchekiller]

Getting my g87 next week looking into tuning it like I did my 340i, anyway what’s the stock fuel system support hp wise I’m assuming somewhere in 700-800 but can it support more?

[GolfCoyote]

Originally Posted by porchekiller

Getting my g87 next week looking into tuning it like I did my 340i, anyway what’s the stock fuel system support hp wise I’m assuming somewhere in 700-800 but can it support more?

Man this could be answered with a fairly simple google search.

700-720whp is about the limit. You’ll need port injection to go higher.

[porchekiller]

Thanks, I searched I really couldn’t find anything. thank you

[Mapper]

Or upgrade the injectors and hpfps

[porchekiller]

Probably safer going direct injection route right? are the HPFP’s the bottleneck first or the injectors

[Dawgz]

Stock fuel pump, HPFP and injectors are limited at E50 (maxed out).

try to aim for E40 for a cleaner setup.

[porchekiller]

Thanks dawgs, noted im used to e30 on b58 so I’ll remember that when I get her tuned

[M4nication]

Idk why people keep saying the HPFP. All you need is the LPFP and injectors (and port injection if your really want to).

I'm on full E85 with PI and stage 2 pure turbos and is still have the stock HPFP. My buddies who have full blown built engines pushing 1000-1200 to the wheels still have the stock HPFP. You don't need to do the HPFP, the stock one is fine.

Further my source for this, is GTP Motorsports, who's my tuner. Who also happens to have the world record for hybrid turbo (basically just twin turbo) S58. Which the guy happens to daily, who is still on the stock HPFP.

[markoz28]

Originally Posted by M4nication

Idk why people keep saying the HPFP. All you need is the LPFP and injectors (and port injection if your really want to).

I'm on full E85 with PI and stage 2 pure turbos and is still have the stock HPFP. My buddies who have full blown built engines pushing 1000-1200 to the wheels still have the stock HPFP. You don't need to do the HPFP, the stock one is fine.

Further my source for this, is GTP Motorsports, who's my tuner. Who also happens to have the world record for hybrid turbo (basically just twin turbo) S58. Which the guy happens to daily, who is still on the stock HPFP.

Any details on your set up? Built engine/trans? Have you done draggy/track/ runs?
How is drivability with your set up?

I’m curious too about the fuel system. I here spool HPFP but only if you are staying DI.

[M4nication]

Originally Posted by markoz28

Any details on your set up? Built engine/trans? Have you done draggy/track/ runs?
How is drivability with your set up?

I’m curious too about the fuel system. I here spool HPFP but only if you are staying DI.

Long post incoming, sorry in advance.

I'm not built engine or trans (yet). I've only had the car since August. But that's in the plans for either later this year or 2025.

As of right now I'm port injection, full E85, Pure stage 2+ turbos, upgraded manifold (Mishimoto) upgraded charge pipes (Mishimoto), intake (Eventuri) catless downpipes, and single midpipe (though midpipe doesn't mean much of anything for power) and XHP transmission tune.

Don't have a dragy yet, but probably will order one this week. Been meaning to get around to it... Numbers I'm at about 820-850 at the wheels (xDrive so AWHP). I could go up to 1000ish at the wheels with my set up and if we fully "turned up" the turbos, but this is about the most can push "safely" with stock internals and stock transmission. Anything more and I will probably send a rod or piston through my hood. So until I do pistons, rods, valve, springs, and studs, I'm staying here.

Absolutely drivable. A huge part of drivability is your tuner, rather than the numbers. A good tuner can make it drivable at any number. Hell even my mpg didn't change much on E85. Well let me rephrase that, if I'm sending it, it guzzles fuel. But if I'm just cruising as normal and not "in boost" the mpg is comparable to when I was stock and on pump gas. Perfectly drivable in traffic too (live in Los Angeles and this is my daily, so drivability was a huge factor for me).

I highly recommend you reach out to GTP. They're local to me, but they remote tune as well. I can't say enough good stuff about them. They have cars all over the country. People have shipped their cars to them from NYC to get the engines built even. Also very fair for pricing.

Back to the pumps, I can't vouch for if you need a HPFP with no PI, but from my understanding, all the guys I know who DON'T have PI and are tuned to the maximum of what their stock system can handle (namely the manifold and fueling), they still have the stock HPFP. My buddy is going full blown engine built (stroker kit and all) and big single turbo conversion. He's still on stock HPFP lol. He should be at about 1200-1400 wheel. So do with that as you will lmao.

[mike@x-ph.com]

you can run 100% E85 with bootmod3 and their flex fuel kit. same power as E50, but you don't need to mix.

[porchekiller]

I’m getting mixed answers here lol but I’m assuming the stock fuel system minus the manifold is good for at least 700hp witch is enough for me in a rwd car, thank you for your answers everyone. If anyone has anything else to add that would be great

[porchekiller]

What point do I need to upgrade the manifold on a side note?

[mike@x-ph.com]

Originally Posted by porchekiller

I’m getting mixed answers here lol but I’m assuming the stock fuel system minus the manifold is good for at least 700hp witch is enough for me in a rwd car, thank you for your answers everyone. If anyone has anything else to add that would be great

"you can run 100% E85 with bootmod3 and their flex fuel kit. same power as E50, but you don't need to mix."


This is from PTF directly.

[Higgs Boson]

IMO, you just run the flex fuel kit and alternate 5-6 gallons of E85 and E10 each time you fill up and youre always in the E40-E50 range, easily checkable on the cluster. No need to run full E85.

[Mapper]

Originally Posted by M4nication

Idk why people keep saying the HPFP. All you need is the LPFP and injectors (and port injection if your really want to).

I'm on full E85 with PI and stage 2 pure turbos and is still have the stock HPFP. My buddies who have full blown built engines pushing 1000-1200 to the wheels still have the stock HPFP. You don't need to do the HPFP, the stock one is fine.

Further my source for this, is GTP Motorsports, who's my tuner. Who also happens to have the world record for hybrid turbo (basically just twin turbo) S58. Which the guy happens to daily, who is still on the stock HPFP.

Because one can forgo doing any PI and separate controller and just upgrade the DI injectors and HPFPs (conveniently controlled by the ECU) as an alternate to go up in power beyond the OE configuration limits.
So yes your specific approach , youdont need to upgrade the HPFPs because YOU are adding fuel through a separate system.

[SigmaShift]

Originally Posted by porchekiller

Probably safer going direct injection route right? are the HPFP’s the bottleneck first or the injectors

From a mechanical perspective yes, but from a tuning perspective, eh. Haven't really seen many tuners nail this down great yet.

[SigmaShift]

Originally Posted by Mapper

Because one can forgo doing any PI and separate controller and just upgrade the DI injectors and HPFPs (conveniently controlled by the ECU) as an alternate to go up in power beyond the OE configuration limits.
So yes your specific approach , youdont need to upgrade the HPFPs because YOU are adding fuel through a separate system.

It's just finding a competent tuner to make this combo work. A lot say they do, but when you get in those cars, they're not so great.

[Schulminator]

Originally Posted by Mapper

Because one can forgo doing any PI and separate controller and just upgrade the DI injectors and HPFPs (conveniently controlled by the ECU) as an alternate to go up in power beyond the OE configuration limits.
So yes your specific approach , youdont need to upgrade the HPFPs because YOU are adding fuel through a separate system.

Haven't really seen anyone go this route yet? Spool looks to be the only ones offering this setup. You have any examples of this setup, as you've noted it in a few different threads.

[Mapper]

I only know of spool at this time. Its the route in progress. Spool says they will work with the tuner. But you are right this is very new... i prefer one control... not to say the PI doesnt work and this is just an alternative. I also dont plan to go into these crazy 1200hp builds.

[Schulminator]

Agreed, I also don’t want to add another system that’s independent of the factory DME’s control & safety.

[SE7EN335]

E60 at around 740whp is the limit for stock fueling and stock turbos. You could also run straight E85 but it is taxing on the fuel system and you won't gain any power over E60. From E50 to E60 on stock fueling and turbos, you can still gain around 10whp.